• Journal of Korea Society of Digital Industry and Information Management
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• v.15 no.1
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• pp.77-86
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• 2019

Comparative analysis to secure safety of Blockchain Many investors have invested in virtual currency such as bit coins as a new investment due to increased popularity of virtual currency around the world. Also, virtual currency such as bit coin has a security technology and it has been relatively proved. popularity of virtual currency is rising as a new investment alternative because of this reason. This paper focused on the block chain's transparency and security of distributed ledger technology, which is relatively safe without third party's intervention. Many governments and companies around the world are developing and working on block chain technological development to introduce due to these reasons However, there are some suggestion that block chain has minor risks to its security. In this paper, it will examine security vulnerabilities from importance of security of Blockchain which relates to transactions of Bitcoin which stored by governments and companies around the world. This paper will propose measure which will improve safety and efficiency of Blockchain technology such as the existing Blockchain method, Blockchain proposal, traceability and awareness about hacking.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.11
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• pp.5234-5251
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• 2018

It is well-known that virtualization technology can bring many benefits not only to users but also to service providers. From the view of system security and resource utility, higher resource sharing degree and higher system reliability can be obtained by the introduction of virtualization technology in distributed cloud. The small size time-sharing multiplexing technology which is based on virtual machine in distributed cloud platform can enhance the resource utilization effectively by server consolidation. In this paper, the concept of memory block and user satisfaction is redefined combined with user requirements. According to the unbalanced memory resource states and user preference requirements in multi-virtual machine environments, a model of proper memory resource allocation is proposed combined with memory block and user satisfaction, and at the same time a memory optimization allocation algorithm is proposed which is based on virtual memory block, makespan and user satisfaction under the premise of an orderly physical nodes states also. In the algorithm, a memory optimal problem can be transformed into a resource workload balance problem. All the virtual machine tasks are simulated in Cloudsim platform. And the experimental results show that the problem of virtual machine memory resource allocation can be solved flexibly and efficiently.

• Journal of the Korea Fashion and Costume Design Association
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• v.15 no.2
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• pp.1-13
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• 2013

The study is to provide basic data on improving costume's fitting by developing physical integrated Basic Bodice Block's development for body types of adult women, which is based on setting up body-type information per truncus as fundamental of adult women's top product manufacture in being ready for Mass Customization era. Also, after review on the objectivity and accuracy of fitting information by real wear and virtual wear experiment on body types, not only 3D virtual clothing system was used as way of information provider of Clothing product, but also provided as basic data in order to use effectively on portion of clothing passion in responding to trend of Mass customization in advance. The consequence of the study is as followings. After analyzing significance differences per items on real and virtual wear evaluation, bowed type of type 1 had significance differences on waist measurement and hip circumference in back and side, which would be knowing as not integrated with costume, affecting form of human body according to virtual wear system bended on back region. Also, in side evaluation, every types except straight body type of type 3 appeared significant differences. In virtual wear evaluation, costume's expression with side body types were not similar to real wear until now except straight body types. It would be improvement things from 3D virtual wear system in advance.

• Journal of Korea Game Society
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• v.17 no.6
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• pp.113-120
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• 2017

With the development of virtual reality technology, in recent years, user-friendly hand gesture interface has been more studied for natural interaction with a virtual 3D object. Most earlier studies on the hand-gesture interface are using relatively simple hand gestures. In this paper, we suggest an intuitive hand gesture interface for interaction with 3D object in the virtual reality applications. For hand gesture recognition, first of all, we preprocess various hand data and classify the data through the binary decision tree. The classified data is re-sampled and converted to the chain-code, and then constructed to the hand feature data with the histograms of the chain code. Finally, the input gesture is recognized by MCSVM-based machine learning from the feature data. To test our proposed hand gesture interface we implemented a 'Virtual Block' game. Our experiments showed about 99.2% recognition ratio of 16 kinds of command gestures and more intuitive and user friendly than conventional mouse interface.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.5
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• pp.409-419
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• 2013

Kinect released by Microsoft in November 2010 is a motion sensing camera in xbox360 and gives depth and color images. However, Kinect camera also generates holes and noise around object boundaries in the obtained images because it uses infrared pattern. Also, boundary flickering phenomenon occurs. Therefore, we propose a real-time virtual-view video synthesis algorithm which results in a high-quality virtual view by solving these problems. In the proposed algorithm, holes around the boundary are filled by using the joint bilateral filter. Color image is converted into intensity image and then flickering pixels are searched by analyzing the variation of intensity and depth images. Finally, boundary flickering phenomenon can be reduced by converting values of flickering pixels into the maximum pixel value of a previous depth image and virtual views are generated by applying 3D warping technique. Holes existing on regions that are not part of occlusion region are also filled with a center pixel value of the highest reliability block after the final block reliability is calculated by using a block based gradient searching algorithm with block reliability. The experimental results show that the proposed algorithm generated the virtual view image in real-time.

• 한국전산유체공학회:학술대회논문집
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• 2006.05a
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• pp.211-214
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• 2006

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.4
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• pp.99-106
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• 2017

With the advent of virtual money such as bit coins, interest in the block chain is increasing. Block Chain is a technology that supports Distributed Ledger and is a versatile technology applicable to various fields. Currently, the block chain is conducting research for various applications such as virtual money, trade finance, marketplace, power market, image contents service, and IoT. The technologies that make up the block chain are smart contract, digital signature/hash function and consensus algorithm. And these technologies operate on P2P networks. In this paper, we have studied e-mail system based on the ethereum which is one of the block chain based technologies. Most legacy mail systems use SMTP and the POP3/IMAP protocol to send and receive e-mail, and e-mail use S/MIME to protect the e-mail. However, S/MIME is vulnerable to DDoS attacks because it is configured centrally. And it also does not provide non-repudiation of mail reception. To overcome these weaknesses, we proposed an e-mail system model based on ethereum. The proposed model is able to cope with DDoS attack and forgery prevention by using block chain based technology, and reliable recording and management among block chain participants are provided, so that it is possible to provide a non-repudiation function of e-mail transmission and reception.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.1_2
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• pp.119-127
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• 2006

Real-time animation of human figures in virtual environments is an important problem in the context of computer games and virtual environments. Recently, the use of large collections of captured motion data have added increased realism in character animation. However, assuming that the virtual environment is large and complex, the effort of capturing motion data in a physical environment and adapting them to an extended virtual environment is the bottleneck for achieving interactive character animation and control. We present a new technique for allowing our animated characters to navigate through a large virtual environment, which is constructed using a small set of building blocks. The building blocks can be tiled or aligned with a repeating pattern to create a large environment. We annotate each block with a motion patch, which informs what motions are available for animated characters within the block. We demonstrate the versatility and flexibility of our approach through examples in which multiple characters are animated and controlled at interactive rates in large, complex virtual environments.

• The Korean Journal of Pain
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• v.35 no.4
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• pp.403-412
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• 2022

Background: Most pain management techniques for challenging procedures are still performed under the guidance of the C-arm fluoroscope although it is sometimes difficult for even experienced clinicians to understand the modified three-dimensional anatomy as a two-dimensional X-ray image. To overcome these difficulties, the development of a virtual simulator may be helpful. Therefore, in this study, the authors developed a virtual simulator and presented its clinical application cases. Methods: We developed a computer program to simulate the actual environment of the procedure. Computed tomography (CT) Digital Imaging and Communications in Medicine (DICOM) data were used for the simulations. Virtual needle placement was simulated at the most appropriate position for a successful block. Using a virtual C-arm, the authors searched for the position of the C-arm at which the needle was visualized as a point. The positional relationships between the anatomy of the patient and the needle were identified. Results: For the simulations, the CT DICOM data of patients who visited the outpatient clinic was used. When the patients revisited the clinic, images similar to the simulated images were obtained by manipulating the C-arm. Transforaminal epidural injection, which was difficult to perform due to severe spinal deformity, and the challenging procedures of the superior hypogastric plexus block and Gasserian ganglion block, were successfully performed with the help of the simulation. Conclusions: We created a pre-procedural virtual simulation and demonstrated its successful application in patients who are expected to undergo challenging procedures.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.585-594
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• 2018

Virtual currencies have emerged along with new technologies such as block chain, artificial intelligence (AI), and big data. This study examines the benefits of a security-enhanced block chain resulting from individual trading, decentralized from governments, as well as the problems associated with misuse of virtual currencies. Virtual currencies, due to its anonymity, is vulnerable to financial crimes, such as ransom-ware, fraud, drug trafficking, tax evasion and money laundering. Use of virtual currencies can facilitate criminals avoid detection from investigative agencies. Government regulatory policy continues to address these concerns, and the virtual currency exchange has also announced a self-regulation proposal. However, a fundamental solution remains necessary. The purpose of this paper is to investigate the problems regarding abuse of virtual currency and to identify a practical system for transactions involving virtual currencies. However, in order to promote transactions involving virtual currencies and to institutionalize a governance system, multilateral cooperation is required. Although the restricting the use of virtual currencies regarding minors and foreign trade, as well as the introduction of a real-name system are considered promising prospects, many problems remain. Virtual currency is not a simple digital item but a method of redesigning the function of money. Coordinated efforts are needed globally to be able to further activate the positive aspects concerning the use of virtual currencies.